<!DOCTYPE html>
<html>
 <head>
  <style type="text/css">

   #tablecell {
     display: table-cell;
   }
   .border { border: 1px solid blue; }

  </style>
 </head>
 <body>

   <span class="border">
      <span id="tablecell">x</span>
   </span>
  
   <script>

   document.body.offsetWidth;
   document.getElementById("tablecell").removeAttribute("id");

   </script>
 </body>
</html>
